Abstract: The energy back coupling system to slows down our country energy supply and demand to have the vital role contradictory, but inverts the technology to hold the important position in the energy back coupling system, mainly introduced one kind of voltage incorporation invertor. First has carried on the system analysis to the voltage invertor, has given the single-phase voltage and the three-phase voltage two kinds incorporates invertor’s ideal electric circuit model. Based on this, has designed one based on the digital signal processor (DSP)TMS320F240 control digitized voltage single-phase incorporation invertor, has built the periphery hardware circuit, and carries on operation processing using the C language, gave the principle simulation result at the same time also to give its experimental result, explained that this kind of invertor’s operating efficiency was high, the reliability was good, the application was also very convenient.
Key word: Energy back coupling; Incorporates the invertor; DSP
0 introductions
Along with our country economy’s rapidly expand, the energy question receives more and more attention now in the society. Is slowing down the energy supply and demand contradictory aspect, the energy back coupling system may play the influential role, main utilization in power situations and so on electronic load, distributional electricity generation and electrical machinery electric regenerative braking. But the electric power electron’s contravariant technology is the energy back coupling system’s hard core.
The digitization is the control technology development tendency, in realizes in specifically the energy back coupling system’s process, should also utilize the digital control mode fully. In the voltage inversion system, takes digital signal processor (DSP) the control center, realizes the peripheral circuit work and the control.
l voltage incorporation invertor’s system analysis
l.l voltage single-phase incorporation invertor’s ideal model
Invertor which uses as the incorporation, the perfect condition generally is:
1) the net side power factor λ=1, namely net side electric current iN is orthoscopic, and with net side voltage uN phase coincidence, such back coupling to electrical network only then active power.
2) can realize the back coupling electric current iN fast adjustment;
3) has the energy two-way flow ability, besides to the electrical network back coupling energy, under the controlled condition, the electric circuit may also be in the rectification pattern, can realize the above ideal contravariant electric circuit condition from the electrical network absorbed energy, and thought that the electric circuit interior has not lost, then obtains ideal model as shown in Figure 1(a).
1.2 three-phase voltage incorporation inversion electric circuit’s model
Voltage three-phase bridge-type inversion electric circuit’s main circuit as shown in Figure 2. May see the three-phase bridge circuit by Figure 2 is the single-phase half bridge electric circuit’s expansion, in the topology is completely similar, each inputs the inductance to be equal, electrical network various phase voltages are a sine wave.
Three-phase incorporation inversion electric circuit’s equivalent circuit model as shown in Figure 3(a), 0 spots are the electrical network center points, 0 ‘ for the direct-current side filter electric capacity center point, Rs are the inductance resistances, other with single-phase circuit. Figure 3(b) is a equivalent circuit measures the chart.
The three-phase incorporation invertor exchange side’s equation is
The contravariant part considered generally the SPWM modulation the three-phase circuit, the three-phase bridge circuit’s steering impulse succession distributed and single-phase similar, the modulation signal for three-phase sine wave uga, ugb and the ugco analysis knowing invertor output line voltage profile is an unipolarity SPWM profile, its output peak-to-peak value is Uio imagination direct-current power supply center point O ‘, then may promote the three-phase SPWM inversion electric circuit phase voltage fundamental wave expression is
Regarding contravariant bridge’s input current id, the result which analyzes by the single-phase circuit, each bridge arm from the direct-current side absorption’s electric current existence second harmonic, in the three-phase circuit each half bridge unit from the direct-current side absorption’s electric current is
After three-phase current superimposition, then obtains the direct-current side electric current id expression is
May know by type (4), when electric circuit under three-phase symmetrical condition, invertor’s input current for constant cocurrent, but does not have the secondary current component, electric circuit’s direct-current side input does not need the second harmonic absorbing circuit. The three-phase invertor loses the person instantaneous power to be also constant along with it, but the single-phase invertor’s input current existence secondary current component, the power input is inconstant, like chart l shows. This is the three-phase invertor is different place of with the single-phase invertor, therefore, the single-phase invertor’s direct-current side filter electric capacity needs to filter high frequency and the low frequency ripple, but the three-phase invertor’s direct-current side filter electric capacity only needs to filter the high frequency ripple then, its capacity may compared to single-phase small.
2 voltage PWM incorporation invertor experiment
In the fore-mentioned theoretical analysis’s foundation, has developed a station base in digital DSP the control voltage single-phase entire bridge PWM incorporation invertor.
2.1 main circuit’s structures and circuit value choice
Digital voltage energy back coupling system’s contravariant main circuit structure as shown in Figure 4. Main circuit’s switch component selects IGBT-IPM module PM75CVAl20, the exchange side for power frequency single-phase 220V, Ui is the cocurrent input voltage, must be bigger than 310 V; Cd1 and Cd2 are direct current the filter electric capacity, LN, for the exchange side filter inductance; A1 is the electric current Hall part, V1. is the voltage examination sensor; K1 is directs current the contact device, K2 is exchanges the contact device; Rc is the direct-current side cushion resistance.
Cocurrent input voltage Ui after filter electric capacity Cdl and Cd2 constant voltage filter inputs the invertor, the single-phase entire bridge invertor outputs after the filter stored energy inductance is direct and person electrical network. Resistance Rc is the electric circuit starts when the cushion filter condenser charge uses, after the charge completes, contact device K1 closed, pipe nipple resistance Rco. The overall system by DSP the chip TMS320F240 control, to the synchronized electrical network signal, the input voltage (V1) and the output current (A1) examination, according to assigns the trigger control pulse, and through contact device K2 decision incorporation time.
2.2 simulations and experimental profile
Using the Matlab simulation, inputs Ui=311V, network voltage UN=220V, inductance value LN=6mH. Uses the amplitude control the PI closed loop adjustment, Figure 5 is assigns the electric current from 5A to 20A when the electric current and the network voltage simulation profile, the electric current rides 10 processing.
Shown in Figure 6 is this system under the split-ring condition the electric current and the network voltage experimental profile, may see the current waveform sine, the phase and the network voltage close (, for, is advantageous for onlooking, electric current signal opposition), the output current size is 5 A. Figure 7 is the inductance both sides voltage experiment profile. Shown in Figure 8(a) is the invertor works when outputs the frequency multiplication PWM profile, 8(b) is the enlarged drawing, the pulse width assumes the sine change.
Figure 9 is the DSP control output pulse signal, the high and low bridge arm has 5 Mu dead areas (low level effective).
The cocurrent input voltage is: 350 V, profile as shown in Figure 10, is quite straight.
3 conclusions
The selective analysis voltage incorporation inversion system, proposed single-phase and the three-phase contravariant system’s theoretical model. In the experiment manufactured a single-phase voltage incorporation inversion system, the system has selected the numerical control method, achieved to the system peripheral circuit’s control. Result which gives from the experiment, may see this system working efficiency is high, the reliability is good, usable.
